Preconception thyroid-stimulating hormone levels and adverse pregnancy outcomes

Area of Science:

• Reproductive Endocrinology
• Maternal-Fetal Medicine
• Thyroidology

Background:

• Inconsistent evidence exists regarding the association between subclinical thyroid dysfunction before conception and pregnancy outcomes.
• Evaluating the relationship between preconception thyroid-stimulating hormone (TSH) levels and adverse pregnancy outcomes is crucial for maternal and fetal health.

Purpose of the Study:

• To investigate the association between preconception thyroid-stimulating hormone (TSH) levels and adverse pregnancy outcomes.
• To determine the risks of composite adverse pregnancy outcomes (CAPOs) associated with varying levels of preconception TSH.

Main Methods:

• Retrospective cohort study of 50,217 women without prior thyroid disease.
• Analysis of preconception TSH levels and their correlation with pregnancy outcomes including pregnancy loss, small for gestational age, large for gestational age, and preterm birth.
• Utilized restricted cubic spline and logistic regression models to assess nonlinear associations.

Main Results:

• A 24.19% incidence of composite adverse pregnancy outcomes (CAPOs) was observed.
• Elevated preconception TSH levels (≥2.1 mIU/L) were associated with increased CAPO risk (OR: 1.04).
• Subclinical hypothyroidism increased CAPO risk (aOR: 1.12), while subclinical hyperthyroidism increased preterm delivery risk (aOR: 1.31).

Conclusions:

• Nonlinear associations exist between preconception TSH levels and adverse pregnancy outcomes.
• Subclinical thyroid dysfunction before conception is associated with an elevated risk of adverse pregnancy outcomes.
• Preconception thyroid screening and management may improve pregnancy outcomes.